<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      // const a = [1, 2, 3, 5]
      // const b = [1, 3, 5, 6]

      function getDifferences(a, b) {
        const arr = a.filter((item) => {
          if (b.indexOf(item) === -1) {
            return item
          }
        })
        return arr
      }
      const res = getDifferences([1, 2, 3, 7, 6, 5], [1, 3, 5, 6])
      console.log(res)
    </script>
  </body>
</html>
